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CVE-2018-6789

An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1.

Critical Known exploited
Severity
9.8 / 10
Critical · CVSS 3.1
Exploit chance (EPSS)
82.14%
Chance of exploitation in the next 30 days. Higher than 99.66% of scored vulnerabilities.
Known exploited
Yes
In CISA's catalog since Nov 3, 2021
Weakness
—
Not classified
Fix
None yet
No fixed version published
Exploited in the wild. Exim Buffer Overflow Vulnerability (Exim Exim). Required action: Apply updates per vendor instructions. Due for U.S. federal agencies by May 3, 2022. Known to be used in ransomware campaigns.

Description

An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1. By sending a handcrafted message, a buffer overflow may happen. This can be used to execute code remotely.

How to fix

No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.

Severity breakdown

CVSS 3.1 9.8

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

References

Advisories

Fixes and patches

Exploits and evidence

Other links

Timeline

  1. Published
  2. Added to CISA's Known Exploited Vulnerabilities catalog
  3. Remediation due for U.S. federal agencies
  4. Last updated by the source
  5. Latest EPSS score
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